Floss: Implement Pandora A2DP profile

Bug: 301000136
Bug: 301036162
Bug: 301036165
Bug: 301000140
Bug: 301036166
Bug: 301036167
Bug: 301037359

Test: mma packages/modules/Bluetooth && pts-bot A2DP
Tag: #floss
Flag: EXEMPT floss only changes
Change-Id: I5e160ecada07029e7aedf59d283d7303421557e5